Produced Water Management Strategy and Water Injection Best Practices: Design, Performance, and Monitoring

Abstract

Summary Key factors in framing a produced water management (PWM) strategy include a company's internal and external environments, technology, and business drivers. Emerging trends for establishing an environment-friendly PWM position comprise adoption of these policies: Move toward zero emissions. No discharge to surface or seas. Waste-to-value conversion. Incremental and progressive separation. Proactive efforts to influence partners, regulators, and environmental laws. This paper covers technical approaches for addressing the production, separation, and disposal/injection segments of water injection and reservoir waterflooding procedures and the basis for selecting strategy components and PWM actions. Best practices result both from comprehensive assessments of current PWM tools and from the insights obtained from a decade-long joint industry project (JIP) on produced water re-injection (PWRI). PWRI for waterflooding or disposal is an important strategy for deriving value from waste while preserving environmental integrity during exploration and production (E&P) operations. Advances in best practices and lessons learned for injector design, operation, monitoring, assessment, and intervention provide the basis for cost minimization and green operations. Facility and subsurface engineering are linked through PWM quality targets, pumping needs, injector completions, and facility constraints. Field cases and data mining results (Abou-Sayed et al. 2005) show the variation in injector responses and underline the key elements contributing to performance. Field evidence indicates that injec-tivities suffer in matrix injection schemes despite the injection of clean water. Alternatively, injectivity maintenance using untreated produced water is feasible. The majority of injectors fracture during injection, thereby impacting facilities' statement of requirement (SOR), injector completion, sweep, and vertical conformance. This paper assesses fracture propagation during seawater and produced water injection and its impact on injector performance. Models depicting plugging of formations and fractures, vertical water partitioning, and well testing are discussed. Best practices are highlighted and the impacts on injection strategy outlined. Several field cases, as well as water injection design and analysis tools for quantifying the impact on flood and well performance, are presented.